A delightful, simple library for aspect oriented programming. Think of Aspects as method swizzling on steroids. It allows you to add code to existing methods per class or per instance, whilst thinking of the insertion point e.g. before/instead/after. Aspects automatically deals with calling super and is easier to use than regular method swizzling. Aspects hooks deep into the class hierarchy and creates dynamic subclasses, much like KVO. There's known issues with this approach, and to this date (February 2019) I STRICTLY DO NOT RECOMMEND TO USE Aspects IN PRODUCTION CODE. We use it for partial test mocks in, PSPDFKit, an iOS PDF framework that ships with apps like Dropbox or Evernote, it's also very useful for quickly hacking something up. Aspects uses _objc_msgForward which causes issues with other code that uses message forwarding.
Features
- Adding aspects returns an opaque token of type AspectToken which can be used to deregister again
- All calls are thread-safe
- Aspects uses Objective-C message forwarding to hook into messages
- Aspects calls and matches block arguments
- Blocks without arguments are supported as well
- Aspect-oriented programming (AOP) is used to encapsulate "cross-cutting" concerns